Leicester boss Richard Cockerill complained of inconsistency among Premiership referees after Friday's 24-20 loss to Harlequins at Twickenham Stoop.
The Tigers' seven-match winning streak in the league came to an end with the defeat and a penalty try awarded by referee Tim Wigglesworth after Leicester's pack disintegrated at a scrum accounted for one of Quins' two tries.
But Cockerill did not blame Wigglesworth for the defeat that has damaged third-placed Leicester's chances of securing a home semi-final in the play-offs.
"What frustrates me is that in three matches this season it has hit double figures in resets before it gets to that point (awarding a penalty try)," said Cockerill.
"I just want to know how it will be refereed because from one week to the next the rules are different.
"I'll ask the question again and will get an answer, but who knows what will happen next. There's no consistency.
"If you're inaccurate at the set-piece, you give penalties away and you concede field position, you're going to get punished and we did.
"Most of the time you get what you deserve and our inaccuracy and indiscipline killed us.
"Quins are a good side, they're dangerous when they're on the front foot and they played well."
Mike Brown scored what proved to be the matchwinning try in the 70th minute after Harlequins had fought back having trailed 10-0 and 13-3 early on.
Fifth-placed Quins are chasing a play-off berth, and their last league match against closest rivals Bath on May 10 could prove to be decisive.
"We'd love for it to come down to us against Bath in that last game," said Harlequins' director of rugby Conor O'Shea.
"If we keep on winning then we'll keep applying pressure and I'm sure there were a few people in the west country who were willing Leicester over the line, but it didn't happen.
"It was a belter of a game that had a bit of everything and more. It's always going to be Titanic between these teams.
"I've never heard the Stoop like that, it was absolutely rocking. We dominated the second half.
"We created a huge amount, we played with ambition and there was a tempo to our game.
"I love seeing us playing like that, it's what we're about. We'll go to Northampton with the bit between our teeth and play. The boys are buzzing and loving their rugby."
O'Shea confirmed that England front-row Joe Marler, who withdrew from the team shortly before the start of the match, has a bruised shoulder and no structural damage.